The invention relates to a balloon catheter for rechanneling stenoses in body passages, in particular of coronary and peripheral arterial vessels, with a balloon through which a guide hose guided by a guide wire extends and which is inflatable with a gas or liquid by way of an inflation tube opening into the interior of the balloon.
Balloon catheters for rechanneling stenoses in coronary vessels have been in use by cardiologists for some time, restenosis in 35% of applications being problematic as the chief late complication of the clinically very successful technique. For this reason, it has been proposed to use laser light for thermal aftertreatment of a balloon dilatation with the aid of a light wave guide (The American Journal of Cardiology 56, 953).
European Patent A 2,182,689 describes a balloon catheter for which the tissue surrounding the balloon is heated with laser light fed into the balloon. From the same source, it is known also that an electric heating element may be provided near the distal end of the guide wire, the element being enclosed by the balloon and heating the fluid present in the balloon. The guide hose extending through the balloon is of a diameter only slightly greater than the diameter of the guide wire to avoid the hazard of coagulation of blood penetrating into the guide hose.
From Biomedizinische Technik 32, September 1987 supplement, 33-36, it is known that high-frequency energy may be used to support balloon dilatation. Thus it is proposed that the balloon catheter be provided with a bipolar electrode configuration of two strip electrodes. The strip electrodes are connected to a generator with a frequency of 0.5 to 1 MHz for a period of up to 38 seconds and an output energy of 50 watts maximum. With high-frequency coagulation in the region of the strip electrodes, animal experiments are to ascertain whether a stabilized dilatation can be achieved.
Another device for thermal treatment of the tissue surrounding body cavities with temperature control means is described in U.S. Pat. No. 4,658,836, a direct heating of the body tissue being effected by electromagnetic radiation in the frequency range of radio waves or microwaves.
German Patent 3,011,322 discloses a radiation probe for a device for microwave treatment of body tissue, at the same time permitting application of hyperthermia and radiotherapy, the tissue being irradiated with microwave energy. To concentrate the microwave radiation on the desired tissular region, the radiation probe, capable of being introduced into a body cavity, is fitted out with a coaxial cable whose unshielded end is asymmetrically surrounded in the probe by a bulbous body.
U.S. Pat. No. 4,662,383 describes a balloon catheter for hyperthermia of tumors, charged by way of a supply line with a coolant capable of being drained from the interior of the balloon by way of an outlet line. In the interior of the balloon, a microwave antenna is provided, having a range of radiation extending into the surrounding tissue. Fluids having a low absorption coefficient for microwaves are provided as coolants, in order not to impede penetration of the microwave into the tissue.